Closed-loop control power system and power control method

Abstract

The invention provides a closed-loop control power system and a power control method, wherein the closed-loop control power system comprises a feedback loop and a direct current (DC) / DC main power converter. The feedback loop not only samples input voltage of the DC / DC main power converter but also samples output voltage. Comparison voltage of the feedback loop is decided by the output voltage. Loop reference voltage of the feedback loop is decided by the input voltage. Feedback voltage is obtained from comparison of the comparison voltage and the loop reference voltage. The feedback voltage is in direct proportion to duty ratio of pulse width modulation (PMW) driving a switch tube of the DC / DC main power converter. When the input voltage is changed, the loop reference voltage of the feedback voltage is accordingly changed. When the input voltage is small, the loop reference voltage is small. When the input voltage is large, the loop reference voltage is large. The duty ratio of the PMW is regulated in real time, and the output voltage is regulated according to the size of the input voltage. The closed-loop control power system and the power control method are capable of reducing circuit consumption, improving power efficiency, and ensuring voltage fluctuation of the output voltage is small when voltage is input in a large range.

Description

technical field [0001] The invention relates to the technical field of switching power supply control, in particular to a closed-loop control power supply system and a power supply control method. Background technique [0002] At present, there are two commonly used control methods for switching power supplies with low output voltage requirements in the communication power supply industry. The two schemes are described in detail below. [0003] see figure 1 , which is a structural diagram of an open-loop control power supply system provided in the prior art. [0004] figure 1 The power system shown is an open-loop control method without loop feedback. [0005] Input voltage V in After being transformed by the DC / DC main power converter 100, the output voltage V out . [0006] Among them, the duty cycle D of the PWM driving the switching tube in the DC / DC main power converter 100 fixed is a fixed value and is not affected by the output voltage V out Impact. [0007]...

AI Technical Summary

Problems solved by technology

[0013] The advantage of this control scheme is that the output voltage V out Stable without fluctuations, but for the input voltage V in For a power supply with a large variation range, the choice of transformer turn ratio is limited, and the turn ratio of the primary winding and the secondary winding has to be reduced. However, the power supply of the communication module is relatively large, the output voltage is low, and the output current is large, which will increase the circuit loss. Reduced power efficiency; also affects device selection

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